JPH0640091B2 - Industrial gas concentration measuring device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an industrial gas concentration measuring device, and more specifically, it is installed on a furnace wall or an exhaust gas passage wall of various fuel furnaces such as an industrial furnace and a boiler. The present invention relates to an industrial gas concentration measuring device for measuring a gas concentration in combustion exhaust gas or an atmosphere in a furnace or an exhaust gas passage.

(Prior Art) Conventionally, as this type of industrial gas concentration measuring device, for example, as shown in FIG. 2, a cylindrical probe for collecting exhaust gas, that is, a measured gas, inserted into various combustion furnaces, A bottomed cylindrical oxygen detection element, which is provided in the probe and is partially exposed to the exhaust gas, and a filter for removing soot and dust in the gas to be measured. The oxygen detection element has, for example, a solid electrolyte having oxygen ion conductivity, for example, a stabilized zirconia porcelain added with calcium oxide or yttrium oxide as a partition wall, and a measurement electrode layer and a reference electrode layer provided on both surfaces of the partition wall, respectively. As the oxygen detector,
One of the electrodes is exposed to the reference atmosphere and the other electrode is exposed to the gas to be measured, and the electromotive force generated by the principle of the oxygen concentration battery is used as the detection signal.

Further, this apparatus generally incorporates a calibration gas introduction pipe for blowing a calibration gas toward a bottomed cylindrical oxygen detection element, and a heater around the calibration gas introduction tube for keeping the oxygen detection element at a constant temperature. .

(Problems to be Solved by the Invention) However, in the oxygen concentration measuring device as described above, most of the constituent parts are fixed to the probe or those which are detachable are limited, and the detection cell unit is limited. And it was not easy to replace the heater.

In addition, when the calibration gas is introduced, cold (compared to the temperature inside the furnace) of the calibration gas is blown out to the vicinity of the detection cell in an instant, so that the detection cell is rapidly cooled, which causes disturbance of temperature control. There was also.

The present invention eliminates such conventional inconveniences and problems, and has a structure capable of easily replacing the detection part and the heater part when they deteriorate and has a temperature difference from the measured gas temperature in the furnace. Another object of the present invention is to provide an industrial gas concentration measuring device which also has a mechanism for introducing a calibration gas with a small amount of gas.

(Means for Solving Problems) An industrial gas concentration measuring apparatus of the present invention is a probe having a calibration gas introduction pipe inserted through a furnace wall or an exhaust gas passage wall of a combustion furnace, and the outside of the probe. A detection cell unit that is inserted from one side and is detachably attached to the probe; and a measurement gas introduction pipe that is inserted from the outside of the detection cell unit and is detachably attached to the probe and the detection cell unit; In an industrial gas concentration measuring device comprising a heater unit that can escape inside a probe, and a calibration gas pipe that passes near the heater unit, between the measured gas introduction pipe and the detection cell unit, It is possible to reheat the calibration gas by providing a gap that forms a calibration gas introduction passage connected to the calibration gas pipe and positioning this gap near the heater unit. In addition, the calibration gas outlet side of the gap is positioned near the base of the detection cell unit so as to surround the outer periphery of the detection cell unit, and the reheated calibration gas is blown out from the calibration gas outlet. It is characterized by having done.

(Operation) Since the detection cell unit and the heater unit are separately and detachably attached to the probe, the detection cell and the heater can be easily replaced. In addition, after mounting all the components, the gap formed between the measured gas introduction pipe and the detection cell unit serves as a passage for introducing the calibration gas, and also serves to adjust the gas flow rate, so that the calibration gas can be used efficiently. Sprayed on the detection cell. When the calibration gas is sprayed onto the detection cell, the gas passage formed by the gap is
Since the gas outlet at the end of the gap surrounds the entire circumference of the detection cell and is located on the base end side of the detection cell, it is blown over the entire circumference from the base end side of the detection cell to the tip side, and the measured gas Can be effectively eliminated and the calibration can be performed quickly.

Further, since the heater is arranged in the vicinity of the gap, the time for heating the calibration gas becomes longer than that in the case where the calibration gas is directly blown from the calibration gas introduction pipe, and the heating area is increased, so that the calibration gas is calibrated. The gas can be brought close to the measured gas temperature.

(Example) As a specific example of the industrial gas concentration measuring device of the present invention, a case of applying to an industrial oxygen concentration measuring device will be described with reference to the drawings.

FIG. 1 is a cross-sectional view of the main part of this apparatus, in which 1 is a cylindrical probe made of metal, for example, stainless steel, and this probe 1 has an inward flange 3 and the inward flange 3 has a probe. A calibration gas introduction pipe 4 is provided which extends inside and projects through the flange 3.
A metallic cylindrical cell support tube 5 is inserted into the probe 1 from the outside. The cell support tube 5 has an outward flange 7 having a hole 6 into which the calibration gas introducing tube 4 can be inserted, and a frustoconical portion 9 having an opening 10 into which a cylindrical detection cell 11 having a bottom can be fitted. And with.

A cylindrical detection cell 11 having a bottom and formed of stabilized or partially stabilized zirconia porcelain is provided on the frustoconical portion 9.
Is fitted with its bottom facing the flange side. By the way, the cell support tube 5 and the detection cell 11 are hermetically sealed by melting a high-temperature inorganic adhesive such as water glass or enamel after pretreatment of coating the ceramics on the adhesive surface of the cell support tube 5 by plasma coating. Is glued to. Preferably, a small amount of a foaming agent is mixed in water glass or the like to absorb the difference in thermal expansion between metal and ceramics.

Next, a cylindrical gas to be measured introduction pipe 15 having an outward flange 13 is inserted from the outside into the cell support pipe 5 inserted into the probe 1. Cell support tube 5 inserted in this way
And the gas introducing pipe 15 are concentrically screwed to the flange 3 of the probe 1 with the flanges 7 and 13 so that the supporting pipe 5 and the introducing pipe 15 are
It can be removable. A porous ceramic filter 10 for dust removal is adhered to the flange side opening 17 of the measured gas introduction pipe 15 by means of alumina cement or the like.

Inside the probe, a stainless steel support fitting 21 inserted from the base end side of the probe extends concentrically with the probe. It has a structure in which the reference gas is introduced by diffusion between the support fitting 21 and the probe 1. Further, a temperature detecting means 23 for measuring the temperature in the vicinity of the detection cell, for example, a thermocouple or the like is attached to the support fitting 21 by a fitting 25.

Further, an outward flange 27 is provided at the tip of the support fitting 21, and a joint flange 29 that abuts against this is screwed with a bolt, a nut, or the like. A heater support tube 35 having an annular heater 33 fixed to the outer peripheral portion is fitted into the inner opening 31 of the joint flange 29, and is adhered by a high temperature inorganic adhesive.

The outward flange 27 and the joining flange 29 are provided with holes 28 and 30 through which the calibration gas introducing pipe 4 can be inserted in the joined state.

On the inner wall of the heater support tube 35, a donut-shaped electric contact 37 is provided via an insulator 38. The contact 37 is, for example, a coil of stainless wire wound into a donut shape. And a ring having a concave cross section for holding the contact terminal. The contactor 37 configured as described above is electrically connected to a positive electrode contact provided on a predetermined outer surface of the detection cell by inserting the detection cell into the contactor 37. In addition, the contact tube 37
22 and a lead wire 41 extending through the interior of the mini insulation tube 39.
Connected to. The material of the lead wire 41 is, for example, stainless steel in consideration of heat resistance. The negative electrode of the detection cell is the electrode terminal 43 provided on the side wall near the bottom of the detection cell.
Then, the platinum lead wire 45 passes through the gas introducing pipe to be measured, is taken out through the ceramic filter 19, and is grounded. Further, a heat insulating material 47 is filled between the outer wall of the heater support tube 35 and the inner wall of the probe 1. The heat insulating material 47 is formed by, for example, forming thin ceramic fiber fibers (for example, “Kauwool” under the trade name) into a block shape by, for example, vacuum forming and sintering the blocks.

In the apparatus configured as described above, a cylindrical gap is formed between the measured gas introduction pipe 15 and the cell support pipe 5 in a state where all the parts are attached, and this gap is formed by the cell support pipe 5. The gas is guided from the gas outlet of the calibration gas introducing pipe 4 penetrating through the gap and extending to this gap, and is blown from the outer periphery to the base side of the detection cell to the tip side of the gas. Further, since the surface area of the gap itself is large, this gap efficiently transfers heat to the calibration gas from the heater 33 located near the cell wall of the cell support tube 5 and the tube wall of the heater support tube 35. Therefore, it is possible to reduce the rapid cooling of the detection cell, that is, the disturbance of the temperature control caused by spraying the calibration gas having a large temperature difference from the gas to be measured on the detection cell. Further, by narrowing the width of the gap, even if the blowing amount of the calibration gas is reduced, the gas flow velocity is high, so that the detection cell can be calibrated sufficiently. For example, the conventional calibration gas is 3000cc
Although it consumes about 500 cc / min, the present invention only consumes about 500 cc / min.

Although one embodiment of the industrial gas concentration measuring device of the present invention has been described above, the present invention is not limited to this embodiment. For example, the gap is not limited to the cylindrical shape, and the shape of the outer wall of the measured gas introduction pipe may be like the teeth of a gear so that a plurality of elongated slits are formed on the circumference. Further, by forming the outer wall of the gas introduction pipe and the inner wall of the cell support pipe into a finger-like shape, it is possible to form a gap that meanders in a cylindrical shape. Since these improve heat transfer properties, it is desirable to have a structure in which the space formed by the gap maintains a small volume while increasing the surface area.

(Effects of the Invention) In the industrial gas measuring device of the present invention, the detection cell unit and the heater unit can be easily replaced, the calibration gas can be effectively heated, and the calibration gas can be made smaller than the conventional one. .

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part showing an industrial oxygen concentration measuring device of the present invention, and FIG. 2 is a sectional view of an essential part showing a conventional example. 1 ... Cylindrical probe, 5 ... Cell support tube 11 ... Detection cell, 15 ... Measured gas introduction tube 21 ... Support metal fitting, 23 ... Temperature detection means 33 ... Heater, 35 ... Heater support tube 37 ... Contact

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Hiroshi Yamada 49-3 Tsurugazawa, Narumi-cho, Midori-ku, Nagoya-shi, Aichi (56) References JP-A-55-85247 (JP, A) JP-A-57 -79444 (JP, A) JP-A-57-204448 (JP, A)

Claims (1)

[Claims] 1. A probe having a calibration gas introduction tube inserted through a furnace wall or an exhaust gas passage wall of a combustion furnace, and a detection cell detachably attached to the probe by being inserted from the outside of the probe. A unit and a measured gas introducing pipe that is inserted from the outside of the detection cell unit and is detachably attached to the probe and the detection cell unit;
In an industrial gas concentration measuring device comprising a heater unit that can be pulled inward of the probe, and a calibration gas pipe passing near the heater unit, between the measured gas introduction pipe and the detection cell unit, A gap is formed to form a calibration gas introduction passage connected to the calibration gas pipe, and the gap is located near the heater unit so that the calibration gas can be reheated. An industrial gas concentration measuring device, characterized in that it is positioned near the base of the detection cell unit so as to surround the outer periphery of the detection cell unit, and that the reheated calibration gas is blown out from the calibration gas outlet.